EXAMPLE #1 Predicting Precipitation Reactions: Predict whether a precipitate
will form when water solutions of silver nitrate, AgNO3(aq), and sodium sulfide,
Na2S(aq), are mixed. If there is a precipitation reaction, write the
complete and net ionic equation that describes the reaction.

Solution:

Step
#1:Determine the possible products using the general double displacement equation.

AB + CD
AD + CB

In AgNO3, Ag+ is A, and NO3- is B. In
Na2S, Na+ is C, and S2- is D. The possible products from the mixture of
AgNO3(aq) and Na2S(aq) are Ag2S and NaNO3. (Remember to consider charge when you determine the formulas for
the possible products.)

AgNO3(aq) + Na2S(aq) to
Ag2S and NaNO3

Step #2: Predict whether either of the possible products is water insoluble.

According to our solubility guidelines, most sulfides are
insoluble, and compounds with Ag+ are not listed as an exception. Therefore,
Ag2S would be insoluble. Silver sulfide is used to make ceramics. Because
compounds containing Na+ and NO3- are soluble,
NaNO3 is soluble.